This applies to derogatory sexual remarks about appearance, behaviour and sexual orientation, unwanted sexual attention, being subject to rumouring, and being shown sexually oriented images, and the like.

The researchers posed questions about sexual harassment experienced in the previous year and received responses from almost 3,000 high school students in two separate studies. The responses paint a clear picture.

Worst for girls
This is not exclusively something boys do against girls. It's just as common for boys to harass boys in these ways.

Girls and boys are equally exposed to unpleasant or offensive non-physical sexual harassment. About 62 per cent of both sexes report that they have experienced this in the past year.

"Teens who are harassed the most also struggle more in general. But girls generally struggle considerably more than boys, no matter the degree to which they're being harassed in this way," Kennair notes.

"Girls are also more negatively affected by sexual harassment than boys are," adds Bendixen.

Being a girl is unquestionably the most important risk factor when teens report that they struggle with anxiety, depression, negative body image or low self-esteem.

However, non-physical sexual harassment is the second most important factor, and is more strongly associated with adolescents' psychological well-being than being subjected to sexual coercion in the past year or sexual assault prior to that.

Level of severity

Bendixen and Kennair believe it's critical to distinguish between different forms of harassment.

They divided the types of harassment into two main groups: non-physical harassment and physically coercive sexual behaviour, such as unwanted kissing, groping, intimate touch, and intercourse. Physical sexual coercion is often characterized as sexual abuse in the literature.

Studies usually lump these two forms of unwanted behaviour together into the same measure. This means that a derogatory comment is included in the same category as rape.

"As far as we know, this is the first study that has distinguished between these two forms and specifically looked at the effects of non-physical sexual harassment," says Bendixen.

Comments that for some individuals may seem innocent enough can cause significant problems for others.

Many factors accounted for

Not everyone interprets slang or slurs the same way. If someone calls you a "whore" or "gay," you may not find it offensive. For this reason, the researchers let the adolescents decide whether they perceived a given action as offensive or not, and had them only report what they did find offensive.

The article presents data from two studies. The first study from 2007 included 1384 high school students. The second study included 1485 students and was conducted in 2013-2014. Both studies were carried out in Sør-Trøndelag county and are comparable with regard to demographic conditions.

The results of the first study were reproduced in the second. The findings from the two studies matched each other closely.

The researchers also took into account a number of other potentially influential factors, such as having parents who had separated or were unemployed, educational programme (vocational or general studies), sexual minority status, immigrant status, and whether they had experienced physical coercion in the past year or any sexual assaults previous to that.

"We've found that sexual minorities generally reported more psychological distress," says Bendixen. The same applied to young people with parents who are unemployed. On the other hand, students with immigrant status did not report more psychological issues. Bendixen also notes that sexual minorities did not seem to be more negatively affected by sexual harassment than their heterosexual peers.

However, the researchers did find a clear negative effect of non-physical sexual harassment, over and beyond that of the risk factors above.

Uncertain as to what is an effective intervention

So what can be done to reduce behaviours that may cause such serious problems for so many?

Kennair concedes that he doesn't know what can help.

"This has been studied for years and in numerous countries, but no studies have yet revealed any lasting effects of measures aimed at combating sexual harassment," Bendixen says. "We know that attitude campaigns can change people's attitudes to harassment, but it doesn't result in any reduction in harassment behaviour."

Bendixen and Kennair want to look into this in an upcoming study. Their goal is to develop practices that reduce all forms of sexual harassment and thereby improve young people's psychological well-being.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.